The disclosure relates to a brake application system for vehicles, particularly rail vehicles, having a device for the emergency release and having a device for the auxiliary release of the brake.
Such a brake application system is known from European Patent Document EP 0 699 846 A2. For an emergency release of the brake, that is, an emergency-caused braking power reduction of the brake affected by braking power, a pneumatic braking actuator supplies the service braking power. For the auxiliary release of the brake not affected by braking power for the purpose of maintenance work, for example, for exchanging brake pads, a threaded spindle of a wear adjuster has to be manually rotated.
The release functions of the brake are previously assigned to separate constructional units of the brake application system—emergency release and auxiliary release. The present disclosure is a single combined device for the emergency and auxiliary release which, in addition, is electrically actuated in a joint drive unit. The construction and the operation of the brake application system are considerably simplified. By means of the electric drive, the auxiliary releasing, which so far had to be carried out manually in a separate manner for each and on each brake application system, can be replaced by a significantly more comfortable, electrically remotely operable auxiliary release which then takes place, for example, from an engineer's cab of the vehicle. In particular, all brake application systems of the vehicle can be released in an auxiliary manner by a joint and one-time control, whereby the maintenance time is significantly shortened. As an alternative, each brake application system can naturally also be actuated in a decentralized manner, for example, by an electric switch arranged under a lockable flap on the superstructure. Finally, the electric control lines can easily be integrated and laid in a space-saving manner in different vehicle models.
The combined device for the emergency release and auxiliary release of the brake may be integrated in a wear adjuster having a helical gear which, as the screwed-together parts, has a threaded spindle and a nut which can be screwed to the threaded spindle. At least one of the screwed-together parts is electrically actuated for the emergency and auxiliary release of the brake. Since the emergency release takes place by the adjuster and not, as in the prior art, by the brake actuator, the emergency release takes place independently of the operability of the brake actuator or its control, which represents an additional safety level. Furthermore, in accordance with a combination of functions, the helical gear is on the one hand used for the wear adjustment and on the other hand for the emergency and auxiliary release of the brake, whereby the installation space and the weight are reduced.
A screw connection part of the helical gear is rotationally actuated by the common electric drive unit for the emergency and auxiliary release. At least during the rotational actuating of the other screw connection part in one rotating direction for the wear adjustment, the one screw connection part is held in a non-rotatable manner. For example, the one screw connection part is coupled with its assigned electric drive unit by an unlockable free wheel which, on the one hand, permits a rotation of the one screw connection part by the electric drive unit in a direction for the adjustment of wear and, on the other hand, is constructed to block this rotation if it is not caused by the electric drive unit.
Furthermore, the other screw connection part may also be actuated by an electric drive unit, specifically independently of an actuation of the electric drive unit of the one screw connection part. As a result, the functions combined in a single helical gear—the wear adjusting, on the one hand, and the emergency and auxiliary release, on the other hand—can be carried out individually and independently of one another, without influencing one another.
Also, the one screw connection part may be a nut, and the other screw connection part may be a spindle of the helical gear. Finally, the unlockable free wheel can be constructed as a space-saving wrap spring free wheel between a cylindrical wall of a non-rotatable part and a sleeve rotating along with the nut.
A coupling may be provided by which, in the presence of an axial force originating from a braking, the other screw connection part can be non-rotatably coupled with a non-rotatable part, such as a housing, and can otherwise be uncoupled from the latter. As a result, the screw connection part loaded by the braking force by the caliper levers of the brake application system is supported on the housing and not on the electric drive unit. Thus, the electric drive unit has smaller dimensions, which contributes to a the reduction of the size.
A slip clutch may be arranged between the electric drive unit and the other screw connection part. The slip clutch is constructed to slip when stop positions are reached and is otherwise coupling. One stop position is formed, for example, by the application of the brake pads on the brake disc, and another stop position is formed by a screwed end position in which the other screw connection part is screwed to the stop into the one screw connection part or vice-versa. In the latter case, the other screw connection part would be rotated along with the one screw connection part, and the rotating movement would be undesirably transmitted to the electric drive unit. The slip clutch therefore protects the electric drive unit from impacts when the stop positions are reached in that it slips in order to permit the motor to softly and gradually conclude its rotating movement and uncouples it from torques introduced by other components. The slip clutch is preferably connected between the coupling and the electric drive unit.
These and other aspects of the present disclosure will become apparent from the following detailed description of the disclosure, when considered in conjunction with accompanying drawings.